NSV 11749: Symbiotic Nova, Not a Born-Again Red Giant

Abstract

NSV 11749 is a little-studied variable star, discovered by W. J. Luyten, which had a long-duration outburst around the year 1903, reaching blue magnitude 12.5 at maximum. Following the outburst, it has apparently been quiescent at about blue magnitude 17 for the past century. It was recently suggested that NSV 11749 may have been a low- or intermediate-mass star that underwent a final helium shell flash, making it temporarily a "born-again" red giant. If so, it would be only the fourth known member of this class, along with V605 Aql, FG Sge, and V4334 Sgr. However, our newly obtained optical and near-IR spectra of the object show that it is instead a symbiotic binary, with strong Balmer and He I-II emission lines, combined with a cool red-giant companion of spectral type M1-2 III. The 1903 outburst was most likely a symbiotic nova event, of which less than a dozen are known at present.

13 pages, 3 figures, Accepted for publication in PASP

References in corpus (6)

• Initial Data Release from the INT Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS)
• IPHAS and the symbiotic stars. I. Selection method and first discoveries
• V605 Aql: The Older Twin of Sakurai's Object
• Raman Scattered O VI $\lambda$ 6825 and the Accretion Disk Emission Model in the Symbiotic Stars V1016 Cygni and HM Sagittae
• DASCH Discovery of A Possible Nova-like Outburst in A Peculiar Symbiotic Binary
• NSV 11749, an elder sibling of the born again stars V605 Aql and V4334 Sgr?

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• A census of symbiotic stars in the 2MASS, WISE and Gaia surveys
• The Distances of the Galactic Novae
• Spectroscopic and photometric analysis of symbiotic candidates -- I. Ten candidates on classical symbiotic stars
• The Bright Symbiotic Mira EF Aquilae
• A primer on the formation and evolution of hydrogen deficient Central Stars of Planetary Nebulæ and Related Objects
• Optical Time-Series Photometry of the Symbiotic Nova V1835 Aquilae